Don't install solidus_auth_devise if it's already in the Gemfile

[gsmendoza]

• Fixes Fix: Ensure that SSF 3.2 doesn't add solidus_auth_devise to the gemfile twice #4766

Goal

Given I have a Rails app
When I add Solidus 3.2.4 to the Gemfile
And I install Solidus with Solidus Starter Frontend and Solidus Auth Devise
Then I should see only one solidus_auth_devise line in the Gemfile.

Current behavior

The Gemfile has two lines for solidus_auth_devise :

# FIXME: Please remove this line if `solidus_auth_devise` appears anywhere else in the gemfile
#        or replace it with a simple `gem 'solidus_auth_devise'` otherwise.
gem 'solidus_auth_devise' unless File.read(__FILE__).lines[__LINE__..-1].grep(/solidus_auth_devise/).any?

gem "solidus_auth_devise"

Cause

This is a workaround to an issue where Solidus#InstallGenerator and SolidusStarterFrontend both add solidus_auth_devise to the Gemfile. From solidusio/solidus_starter_frontend@b9e8a7f:

Adding solidus_auth_devise to the Gemfile was conflicting with it
being added by the solidus installer again unless
`--with-authentication=false` was provided. But the auth extension
is also required by SSF. This forced a workaround in which we skip
the `gem` entry in the Gemfile if another entry for the same gem is
present in any of the following lines. It's ugly but puts a bandaid
that will at least allow the installation to succeed.

Testing

I have confirmed manually that, in conjunction with the SolidusStarterFrontend update, installing Solidus in v3.2 now installs solidus_auth_devise only once. See

• https://github.com/solidusio/solidus_starter_frontend/commits/gsmendoza/sol-547-fix-ensure-that-ssf-32-doesnt-add
  • This update to SolidusStarterFrontend removes the SolidusAuthDevise workaround and FIXME comment.
• https://github.com/nebulab/solidus/tree/gsmendoza/sol-547-fix-ensure-that-ssf-32-doesnt-add--with-test-ssf-branch
  • A branch of this PR that ties InstallGenerator to a branch of SolidusStarterFrontend without the workaround.
• https://github.com/gsmendoza/solidus_store/tree/rails-7-0-4--solidus-3-2-4--sol-547-fix-ensure-that-ssf-32-doesnt-add
  • The app generated by the Solidus installation I did to test this fix.
• solidus-install-log.txt
  • The log of the Solidus installation. Note the "skipping solidus_auth_devise is already in the gemfile" line.

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[elia]

Left an optional nit, fine by me if we merge without changing anything 🙌

[waiting-for-dev]

Leaving some comments to understand everything, but it looks great ❤️

[gsmendoza]

@waiting-for-dev @solidusio/core-team I don't have any more updates to this PR. Can you take a look again? Thank you!

[gsmendoza]

@waiting-for-dev I extracted the method to uncached_dependencies. Can you take one more look? Thank you!